Particle-applicating device

ABSTRACT

A particle-applicating device for printing apparatus having a printing surface on which is formed electrical or magnetic charge patterns for attracting the particles. A first flat vibrating plate is provided proximate to the printing surface and is pivotally coupled to a vibration generating arrangement. A particle dispenser is arranged to deposit, near one end of the vibrating plate, successive uniform quantities of particles to be applied to the charge pattern. The vibrating motion imparted to the plate enables a uniform movement of the particles along the plate&#39;&#39;s upper surface and a uniform projection of the particles onto the printing surface situated thereabove. A second vibrating plate and arrangement is provided below the first plate to collect the unattracted particles and return them by oppositely directed vibratory motion to the particle dispensing area.

United States Patent Staller [54] PARTICLE-APPLICATING DEVICE- [72] Inventor: Karel Jan Staller, Rutherford, NJ.

[73] Assignee: international Telephone and Telegraph Corporation, Nutley, NJ.

[22] Filed: Jan. 22, 1969 [21] Appl.No.: 793,034

[52] U.S.Cl ..355/3,1l8/212,118/637 [S1] lnt.Cl. ..G03g 15/00 [58] FieldofSearch ..118/637,2l2,637E;355/3 [56] References Cited UNITED STATES PATENTS 3,007,147 10/1961 Johnson ..200/61.21

3,140,199 7/1964 York ..118/637 3,358,594 12/1967 Thompson .1l8/637X 3,511,214 5/1970 Hodges ..118/637 5 an..."-.uquunnununuumm Primary Examiner-Samuel S. Matthews Assistant ExaminerMichael D. Harris Att0rneyC. Cornell Remsen, Jr., Walter J. Baum, Percy P. Lantzy, Philip M. Bolton, Isidore Togut and Charles L. Johnson, Jr.

[5 7] ABSTRACT A particle-applicating device for printing apparatus having a printing surface on which is formed electrical or magnetic charge patterns for attracting the particles. A first flat vibrating plate is provided proximate to the printing surface and is pivotally coupled to a vibration generating arrangement. A particle dispenser is arranged to deposit, near one end of the vibrating plate, successive uniform quantities of particles to be applied to the charge pattern. The vibrating motion imparted to the plate enables a uniform movement of the particles along the plates upper surface and a uniform projection of the particles onto the printing surface situated thereabove. A second vibrating plate and arrangement is provided below the first plate to collect the unattracted particles and return them by oppositely directed vibratory motion to the particle dispensing area.

7 Claims, 2 Drawing Figures PATENYED FEB 1 I972 m IQVENTOF? KAREL .1. STALLER W W ATTORNEY PARTlCLE-APPLICATING DEVICE BACKGROUND OF THE DISCLOSURE In general this invention relates to a particle-applicating device for use in printing apparatus, and more particularly to a particleapplicating device for printing apparatus wherein particles are projected against the printing surface and retained by the force from a plurality of electrical or magnetic islands formed on its surface.

In many existing printing arrangements which utilize such particles, the copy which is produced is not as clear as possible and continual improvement is sought as to the quality of printout. One of the key points to consider in improving the quality of printout copy is the manner of applying the particles onto the magnetic or electrically charged islands formed on the surface of the printing apparatus. The present arrangements either apply too many particles on one island, so that the letters become blurred on transfer, or too few particles, making the printout poor or even unreadable. Another serious problem in the case of excessive application of particles is the inherent problem of cleanup of the printing apparatus after transfer.

All of these problems are becoming even more serious with the increasing speed at which the recording and printout arrangements can now operate. The faster the speed the more important is the even application of the particles with the least amount of cleanup while still maintaining good copy. It has also been observed that many arrangements in high speed apparatus utilize different types of air pressure for applicating the particles with considerable trouble. Mechanical applicators presently employed do not transport and project the particles in a controlled manner against the printer surface so that the high speed and high quality printout is possible. This is due to an even amount of particles being projected against all the electrostatic or magnetic island as the printing surface passes the applicating device.

The embodiments for the particle-applicating device which has been developed for use on the very high speed printers, may also be used to improve the quality of slower printers as will become evident during the detailed description.

SUMMARY OF THE INVENTION It is an object of this invention to improve the quality of copies from printing apparatus by a new particle-applicating device. It is therefore a further object of this invention that the particles which are retained on the surface by electrical or magnetic forces are propelled against that surface by a mechanical vibrating arrangement.

According to the broader aspects of this invention, there is provided a printing apparatus wherein particles are attracted to a plurality of electrical or magnetic islands formed on a surface, the particle-applicating device including means for providing a source of particles, a vibrating means for carrying BRIEF DESCRIPTION OF THE DRAWINGS Other features and objects of this invention, not specifically enumerated above, will become evident during the detailed description which follows in connection with the accompanying drawings in which:

FIG. 1 illustrates one useful embodiment a particle-applicating device according to the invention in conjunction with a printing drum; and

FIG. 2 illustrates another applicating device according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. I illustrates a printing drum ll rotating in the direction illustrated by arrow 12. The drum includes a ferromagnetic coating 13 on which, by means of a magnetic printing head 14, is formed a plurality of small magnetic islands illustrated as dots 15, the combination of dots may form any image desired. The formed magnetic islands are then carried past, in the usual manner, a particle-applicating device of the type to which this invention is directed.

The applicating device includes an upper vibrating flat plate 16 which is pivotally mounted at each end 17 to a spring-type lever 18 which is either pivotally fixed at the other end 19 or adjustable along are 20. The electromagnets 21 have their armatures 22 attached to the spring levers l8, and the energizing coils 23 are adjustable by means 24 in relation to the armatures 22. By energizing and deenergizing the coils 23, oscillation of the spring levers 18 is caused due to its spring characteristics. This oscillating motion 25 is at a 45 angle with the upper vibrating flat plate 16.

It should be noted here that although there is illustrated electromagnetic coils which are movable to adjust the air gap 26 between the coil face and the armature, it is also possible that the armature and spring lever could be adjustably mounted to vary the gap 26.

The oscillating motion 25 of the spring lever in this 45 attitude transmits a vibrating motion to upper plate 16 and causes the particles to move along the plate 16 in the direction indicated by the arrow 28 in decreasing arcs 27. At the point nearest the drum, the apex 29 of the projected arc 27 is against the magnetic islands to be attracted and retained by the magnetic forces in an even manner.

It should be understood that the reason that the electromagnets are made adjustable is so that the oscillations 25 can be controlled in amplitude and frequency, and thereby control the height of the arc and the amount of particles that may be retained by any particular island.

In a similar manner, a lower vibrating flat plate 30 may be utilized to return the particles in the direction of arrow 31 to the source 32. This lower plate is caused to vibrate by another pair of electromagnets 33 having their associated armatures 34 and spring levers 35 positioned at a angle with respect to the levers .18 of the upper plate. This angular change will cause the reverse motion of the particles in the direction 31. Though not illustrated, lower electromagnets 34 may be adjustably mounted to vary the airgap and control the amplitude and frequency of the oscillation. This is not as important, however, since it is not necessary that the particles be returned in an even manner to the particle chamber 32'.

The chamber 32 contains an elevator 36 which is adapted to carry powder particles from the supply point to a powder volume'calibrating wheel 37. The wheel 37 has contoured surfaces 38 into which the powder particles 32 from the elevator are deposited. The excess brush wheel 39 insures that successive uniform quantities of magnetic particles are discharged by wheel 37 onto the upper vibrating plate 16. This enables an even flow of magnetic particles from the source to the printing drum as the vibratory motion will provide unifonn motion of these quantities along the plate and uniform projection thereof onto the drum surface. Thus the novel applicator moves the particles along the upper vibrating plate by controlled oscillations so that the particles are projected against the drum in a manner which insures a high quality dusting of the magnetic islands.

Another embodiment in keeping'with the ideas presented in this invention isillustrated in FIG. 2. A printing drum 40 is shown wherein an optical system 41 creates electrically charged islands 42 on the selenium surface 43 thereof. It should be noted that although an electrostatic printing arrangement is described in connection with FIG. 2, the applicating devices of both figures could be interchanged.

The image formed in the selenium surface is moved as indicated by the arrow 44.toward the applicating device 45 which includes an-elastic belt 46 carried around a pair of pulleys 47, one of which may be driven. Adjacent the point of I contact between drum and belt are a number of eccentrics 48 each having a plurality of protuberances 49. The eccentrics 48 are continually rotating while the elastic belt is moving in the direction of arrow 50. The impacts of the protuberances with the belt causes the oscillating motion indicated by the projections 51. The height and velocity of these projections can be controlled by the movement of the eccentrics in the direction of arrow 52 and by the speed of rotation. The particles used, in the case of a selenium system, comprise electrically charged nonmagnetic particles 53 which are oppositely charged to be attracted and retained by the charged islands, and a plurality of glass balls 54. The glass balls and the nonmagnetic particles are carried along the belt and projected against the printing surface by the rotation of the eccentrics.

The tiny glass balls 54 are included in the mixture to aid returning the nonmagnetic particles to the source 55. The glass balls force the nonmagnetic particles along within the channel 56 so that they are propelled around the backside 57 of the belt. The backside issupported by channel support 58 to prevent flexing a deflector scraper 59 within the chamber 60. The combination of the nonmagnetic particles and tiny glass balls is carried by the elevator 61 as shown and deposited on the elastic belt 46 in a continuous manner.

The applicating device of FIG. 2 utilizes a plurality of eccentrics having a number of protuberances which imparts a constant vibrating motion to the elastic belt in the illustrated area while it is continuously moving. The motion projects the nonmagnetic particles and glass balls against the electrically charged islands. Only the charged particles are retained and the glass balls cooperate to return the charged particles which were not retained by the charge force islands on the selenium surface. The speed and relative position of the eccentrics will control the height of the projections and the quantity of particles thrown against the drum which in turn controls the quality of copy produced.

As described above in connection with the drawings, a particle-applicating device has been designed with mechanical vibrating means which are used for carrying the particles from a source to a position adjacent a printing surface against which, by means of the vibrations, they are thrown against and retained by attractive forces during the apex of their projection.

Iclaim:

1. ln a printing apparatus wherein particles are attracted to a charge pattern formed on a recording surface, a particle applicating arrangement comprising:

a. means providing a source of magnetic particles;

b. a first vibrating plate having a horizontally arranged flat upper surface positioned proximate to at least a portion of the recording surface, said upper surface being arranged to receive the particles from said source and to cause the magnetic particles to be projected against the recording surface to enable their retention by the charge pattern substantially during the apex of their projection; and

c. vibrating means coupled at an acute angle to the first vibrating plate, and arranged to vibrate at said acute angle to said first vibrating plate and enabling therefrom a simultaneous uniform propelling of the particles along said flat upper surface and projection of successive substantially uniform quantities of the particles against said portion of the recording surface.

* 2. The arrangement according to claim 1 wherein said 7 vibratingmeans include at least one electromagnet having its armature attached to a spring lever, said spring lever being pivotally mounted at one end and pivotally attached to said plate at the other end, said lever being caused to oscillate via said electromagnet, imparting thereby a resultant vibratory motion to said first plate causing the movement and projection of the particles along said upper surface thereof and against the recording surface.

3. The arrangement according to claim 2 further comprising means for returning to said source the excess particles unattracted to the charge pattern, said returning means including a second-vibrating flat plate positioned substantially beneath said first plate to catch the unattracted particles and return them to said source, the vibratory motion of said second plate being provided by said vibrating means.

4. The arrangement according to claim 3 wherein said vibrating means include. a second electromagnet and associated spring lever pivotally coupled to said second plate, said second electromagnet and associated spring lever being arranged to provide a vibration for moving the particles along the upper surface of said second plate in a direction opposite to that of particle motion along said first plate.

5. The arrangement according to claim 4 wherein said means providing a source of particles include a chamber, having therein an elevator arranged to collect the particles stored in said chamber, and a particle dispenser positioned in said chamber and arranged to receive predetermined amounts of the particles collected by said elevator arrangement, said dispenser providing successive uniform quantities of particles to be dispensed onto said first plate.

6. The arrangement according to claim 4 further including a printing head positioned to form charge patterns on a ferromagnetic coating of the recording surface, and wherein the particles which are projected against the charge patterns are magnetic and are retained by magnetic forces during movement of the recording surface away from the particle-applicating device.

7. A particle applicating arrangement for a magnetic printing drum in which magnetic charge patterns are formed on the drum by a magnetic printing head, the arrangement comprismg:

a. a source of magnetic particles;

b. an upper vibrating plate for transporting said particles past the drum, so that said magnetic particles are projected against the drum surface and retained by magnetic attraction;

c. first electromagnet means coupled to said vibrating plate and adapted to transmit vibratory oscillations to said upper vibrating plate so as to cause said particles to be simultaneously transported along said upper vibrating plate and projected against the drum surface;

d. a lower vibrating plate positioned to receive the unattracted magnetic particles from said upper vibrating plate and to transport said particles along its surface and return them to said source;

e. second electromagnet means coupled to said lower vibrating plate and positioned to oscillate in a direction perpendicular to said first electromagnet means to cause the return movement of said magnetic particles to said source;

f. means for dispensing successive uniform amounts of particles on said upper vibrating plate, said dispensing means including an elevator, a particle volume measuring drum having equal measuring cavities on its circumference, and an excess powder brushing device positioned to uniformly control the amount of powder particles received in said cavities, said dispensing means depositing successive uniform quantities of particles on said upper vibrating means for transport thereby to the position where they are projected against the magnetic charge patterns on the drum; and

g. means for adjusting the vibratory movement of said upper vibrating plate to control the projection of the powder particles against the drum surface. 

1. In a printing apparatus wherein particles are attracted to a charge pattern formed on a recording surface, a particle applicating arrangement comprising: a. means providing a source of magnetic particles; b. a first vibrating plate having a horizontally arranged flat upper surface positioned proximate to at least a portion of the recording surface, said upper surface being arranged to receive the particles from said source and to cause the magnetic particles to be projected against the recording surface to enable their retention by the charge pattern substantially during the apex of their projection; and c. vibrating means coupled at an acute angle to the first vibrating plate, and arranged to vibrate at said acute angle to said first vibrating plate and enabling therefrom a simultaneous uniform propelling of the particles along said flat upper surface and projection of successive substantially uniform quantities of the particles against said portion of the recording surface.
 2. The arrangement according to claim 1 wherein said vibrating means include at least one electromagnet having its armature attached to a spring lever, said spring lever being pivotally mounted at one end and pivotally attached to said plate at the other end, said lever being caused to oscillate via said electromagnet, imparting thereby a resultant vibratory motion to said first plate causing the movement and projection of the particles along said upper surface thereof and against the recording surface.
 3. The arrangement according to claim 2 further comprising means for returning to said source the excess particles unattracted to the charge pattern, said returning means including a second-vibrating flat plate positioned substantially beneath said first plate to catch the unattracted particles and return them to said source, the vibratory motion of said second plate being provided by said vibrating means.
 4. The arrangement according to claim 3 wherein said vibrating means include a second electromagnet and associated spring lever pivotally coupled to said second plate, said second electromagnet and associated spring lever being arranged to provide a vibration for moving the particles along the upper surface of said second plate in a direction opposite to that of particle motion along said first plate.
 5. The arrangement according to claim 4 wherein said means providing a source of particles include a chamber, having therein an elevator arranged to collect the particles stored in said chamber, and a particle dispenser positioned in said chamber and arranged to receive predetermined amounts of the particles collected by said elevator arrangement, said dispenser providing successive uniform quantities of particles to be dispensed onto said first plate.
 6. The arrangement according to claim 4 further including a printing head positioned to form charge patterns on a ferromagnetic coating of the recording surface, and wherein the particles which are projected against the charge patterns are magnetic and are retained by magnetic forces during movement of the recording surface away from the particle-applicating device.
 7. A particle applicating arrangement for a magnetic printing drum in which magnetic charge patterns are formed on the drum by a magnetic printing head, the arrangement comprising: a. a source of magnetic particles; b. an upper vibrating plate for transporting said particles past the drum, so that said magnetic particles are projected against the drum surface and retained by magnetic attraction; c. first electromagnet means coupled to said vibrating plate and adapted to transmit vibratory oscillatIons to said upper vibrating plate so as to cause said particles to be simultaneously transported along said upper vibrating plate and projected against the drum surface; d. a lower vibrating plate positioned to receive the unattracted magnetic particles from said upper vibrating plate and to transport said particles along its surface and return them to said source; e. second electromagnet means coupled to said lower vibrating plate and positioned to oscillate in a direction perpendicular to said first electromagnet means to cause the return movement of said magnetic particles to said source; f. means for dispensing successive uniform amounts of particles on said upper vibrating plate, said dispensing means including an elevator, a particle volume measuring drum having equal measuring cavities on its circumference, and an excess powder brushing device positioned to uniformly control the amount of powder particles received in said cavities, said dispensing means depositing successive uniform quantities of particles on said upper vibrating means for transport thereby to the position where they are projected against the magnetic charge patterns on the drum; and g. means for adjusting the vibratory movement of said upper vibrating plate to control the projection of the powder particles against the drum surface. 